Integrate PDF conversion

The converter runs on Node.js and returns PDF bytes. Keep conversion on the server for browser applications. The package uses the EigenPal Pro License.

Install the converter and its engine peer:

npm install @docx-editor.dev/docx-to-pdf @docx-editor.dev/core

Return a PDF response

A Node.js route can return the bytes in a web Response. This handler accepts raw DOCX bytes, not multipart form data:

import {
  exportPdf,
  ExportResourceError,
  PdfDocumentOpenError,
  PdfFidelityError,
  PdfOutputLimitError,
  PdfPageLimitError,
} from '@docx-editor.dev/docx-to-pdf';

export async function POST(request: Request): Promise<Response> {
  try {
    const source = new Uint8Array(await request.arrayBuffer());
    const result = await exportPdf(source, {
      signal: request.signal,
      timeoutMs: 30_000,
      maxPages: 100,
      maxOutputBytes: 16 * 1024 * 1024,
      useSystemFonts: false,
    });
    return new Response(new Uint8Array(result.bytes), {
      headers: {
        'Content-Type': 'application/pdf',
        'Content-Disposition': 'attachment; filename="document.pdf"',
        'Cache-Control': 'no-store',
      },
    });
  } catch (error) {
    if (error instanceof PdfDocumentOpenError) {
      return Response.json({ error: error.code }, { status: 422 });
    }
    if (error instanceof PdfFidelityError) {
      return Response.json({ error: error.code }, { status: 422 });
    }
    if (error instanceof PdfPageLimitError || error instanceof PdfOutputLimitError) {
      return Response.json({ error: error.code }, { status: 413 });
    }
    if (error instanceof ExportResourceError && error.code === 'timedOut') {
      return Response.json({ error: error.code }, { status: 504 });
    }
    throw error;
  }
}

Configure your server's request size limit before request.arrayBuffer() reads the body. The output byte limit does not limit uploaded bytes.

Limit concurrent conversions to fit your available memory.

Next.js

Use export const runtime = 'nodejs' in the route file. Place the handler in app/api/convert/route.ts.

Keep packages external so Node.js resolves their font and WebAssembly assets:

// next.config.mjs
export default {
  serverExternalPackages: [
    '@docx-editor.dev/docx-to-pdf',
    '@docx-editor.dev/core',
    '@docx-editor.dev/fonts',
  ],
};

If you deploy a standalone bundle, include the converter's assets/ directory and the fonts package's assets. Keep the package directory structure intact. Test the deployment artifact with a real conversion before release.

Convert a batch

Process a batch sequentially when memory use matters more than throughput:

import { readFile, writeFile } from 'node:fs/promises';
import { exportPdf } from '@docx-editor.dev/docx-to-pdf';

for (const name of ['first', 'second']) {
  const source = await readFile(`${name}.docx`);
  const result = await exportPdf(source, { useSystemFonts: false });
  await writeFile(`${name}.pdf`, result.bytes);
}

The exporter disposes its document session after each call, including failed calls.

Next steps

Export both formats with Compare PDF and Markdown conversion.
Configure deadlines and memory isolation with PDF export API.